Bridges

SDOT owns, inspects, maintains, and/or operates almost 280 bridges.

The goal of the Bridge Program is to extend the service life of our bridges, maintain their historic character, provide safe travel for all, and protect the public's investment. We achieve these goals efficiently and cost effectively by practicing innovative maintenance management.

Read more below to learn about Seattle's bridges, how to use them, and how we are working to maintain and improve them.

Pictured: The Aurora, Fremont, and Ballard Bridges

Some of Seattle's bridges, like the West Seattle Bridge, make connections over bodies of water. Other bridges, like the Magnolia Bridge, are viaducts that make connections over valleys. Some bridges, like the Fremont Bridge, serve all travel modes. Others, like the W Thomas St Overpass, are limited to foot or bike traffic.

Enforcing maximum vehicle loads on bridges is important to maintaining bridge safety and long-term health. See the chart below for current weight restrictions by structure:

Click here to learn more about bridge weight limit signs.

For information regarding Commercial Vehicle Permits please contact [email protected], call (206) 684-5086, or visit the webpage.

Seattle has seven vehicular, moveable bridges over navigable water. Four of these are owned by SDOT. Federal law requires bridges open for marine traffic, with few exceptions. Seattle is part of the US Coast Guard 13th District. More information is available at www.uscg.mil/d13/.

Learn about where these bridges are located and used for vehicular travel below:

Here is a list of vehicular bridges in Seattle that open for marine traffic:

1956, northbound

1996, southbound

To see the current federal regulations around opening the Lake Washington Ship Canal bridges, click here.

Information regarding changes in bridge operations is located on United States Coast Guard Local Notice to Mariners website.

Bridges open on request between 7 AM and 11 PM.

From 11 PM to 7 AM, bridges open by appointment only.

The average bridge opening, from the time street traffic stops to the time it resumes, lasts about 4 minutes. The Spokane St Swing Bridge openings last about 10 minutes.

Seattle's Ship Canal Bridges - University, Fremont, and Ballard Bridges - have restrictions in place during the morning and afternoon peak commute to help keep street traffic moving during busy hours. These 3 bridges stay closed to marine traffic on weekdays, from 7-9 AM and from 4-6 PM, except for federal holidays but Indigenous Peoples' Day and for any vessel of 1,000 gross tons or over.

See the federal regulation for Lake Washington Ship Canal bridges here.

Information on Montlake Bridge openings is available here.

Pictured: South Park Bridge

Between 7 AM and 11 PM: Vessels should contact the bridge by radio (Marine Channel 13), call (206) 386-4251, or use a whistle signal: one long, one short.

From 7 AM to Dusk: The US Coast Guard requests pleasure vessel use a whistle signal.

Between 11 PM and 7 AM: Bridge openings are by appointment only and should be requested no less than 1 hour prior to the opening.

For openings by appointment for the Ship Canal Bridges, the bridge operator will wait 15 minutes after the appointment time before contacting the vessel on Marine Channel 13. If the bridge operator doesn't receive a response, the operator will leave for the next appointment.

For state- or county-owned bridges, visit www.kingcounty.gov or www.wsdot.wa.gov.

Our moveable bridges operate with complex mechanical and electrical equipment. Though they are rare, issues with these systems can happen. When an outage occurs, our roadway structures crew and engineers work as fast as possible to restore service to the traveling public. To quicken our response, we maintain a Stand-By Crew during weekday off hours as well as weekends and holidays. This crew consists of a lead supervisor, mechanic, and electrician. 

When our roadway structures crew learns of an issue, they take the following steps to get the bridge up and running: 

Mechanical and electrical systems experience ordinary wear and tear over their service life. We have a strong, proactive maintenance system in place to address these issues and keep our bridges in good working condition.

Experiencing a travel delay related to a moveable bridge or have questions about its status? Follow @SDOTtraffic on Twitter for real-time updates.

Pictured: The Fremont Bridge over the Lake Washington Ship Canal

As of 2022, we own, inspect, maintain, and/or operate almost 280 bridges. This is in addition to nearly 1,500 other types of roadway structures—like retaining walls, stairways, and underground support walls. All these structures need ongoing maintenance, inspections, monitoring, and preservation. We are committed to continuing a thorough and proactive asset preservation program. This maximizes the life of our infrastructure so we can rely on it to remain safe and operational.

Bridge program work includes:

Read more below to learn how we’re going above and beyond to maintain, rehabilitate, replace and proactively invest in our bridges:

Our proactive maintenance approach means we work to prevent issues with our bridges and roadway structures before they happen.

Examples of proactive maintenance include:

Check out our blog to learn more in detail how we work to preserve and maintain our bridges to withstand the test of time.

We are actively working on several bridges in the city. Visit the project webpages below to learn more:

Bridge

Updated Status

Below is a list of completed bridge rehabilitation or replacement projects:

Pictured: Building of the Ballard Bridge, 1939

Pictured: the Ballard Bridge and Salmon Bay, taken in 1950

Pictured Left: Concrete is poured into a form on the underside of the Ballard Bridge as part of the seismic retrofit project, 2013.

Pictured Right: Jackets were installed and then filled with concrete around the columns on the Ballard Bridge to strengthen it against earthquake damage, 2013

Pictured: Ballard Bridge, 2017